B1.2 Flashcards
What does Homeostasis mean?
Maintaining a constant internal environment by reacting to the external environment.
What does osmoregulation mean?
The process that regulates water content
What happens when you’re too hot?
- you sweat (evaporates and carries away heat energy)
- Hairs lie flat (Prevent trapping of heat)
- Blood vessels dilate (allows blood to surface of skin, blood cause heat energy to be lost)
What happens when you’re too cold?
- shiver (muscles contract to release heat)
- Hair stands on end (trapping a layer of air-heat energy)
- blood vessels constrict(less blood flows through to the skin meaning less heat it lost)
What is the hypothalamus?
Part of the brain which detects a change in temperature and sends nerve impulses to the sweat glands
What does negative feedback mean?
When your body reverses its change back to its original state
What does vasoconstriction mean?
Blood vessels narrow, blood flow to the skin is reduced and heat loss is decreased.
What does vasodilation mean?
Blood vessels widen, blood flow to skin is increases to skin and increases heat loss.
What is CNS?
The central nervous system which consists of brain, nerves and the spinal chord.
Stages in the reflex arc?
Recepter- sensory neurone- relay neurone- motor neurone- effector
What are synapses?
Gap between the neurones
What are neurotransmitters?
Chemical messages that carry info along the synapse
How are stimuli and responses linked?
Stimulus- receptor - sensory neurone- cns- motor neurone - effector - response
What do sensory neurones send impulses between?
from the sense organs to the cns
What do motor neurones send impulses between?
from the cns to effector organs
What is an axon?
fibres that carry electrical impulses from the cell body to the dendrites.
What is an Dendron?
Fibre that carries electrical impulses to the cell body
What cause involuntary and voluntary responses?
Involuntary responses are caused by the spinal chord
- voluntary responses are caused by the brain
What is the myelin sheath?
A fatty substance surrounding dendrons and axons that speeds up the nerve impulses along the neurones.
Where are hormones produced?
Produced and released by glands in the endocrine system. They are released into the bloodstream and have an affect on target organs
What happens when your blood glucose is too high?
Insulin is release into the pancreas and converts glucose into glycogen which is stored in the liver.
What happens when your blood glucose is too low?
Glucagen is released from the pancreas which helps convert glycogen into glucose which is released into the bloodstream.
What is type 1 diabetes?
The pancreas does not produce enough insulin so to treat it people have daily injections of insulin.
what is type 2 diabetes?
Pancreas produces insulin but the body becomes insensitive to it. Can be treated by careful eating, exercise and losing weight.
